Simulation Methodology for Coupled Fire-Structure Analysis: Modeling Localized Fire Tests on a Steel Column

Advanced simulation methods are needed to predict the complex behavior of structures exposed to realistic fires. Fire dynamics simulator (FDS) is a computational fluid dynamics code, developed by NIST for fire related simulations. In recent years, there has been an increase in use of FDS for performance-based analysis in the area of structural fire research. This paper discusses the FDS-finite element method (FEM) simulation methodology for structural fire analysis. The general methodology is described and a validation study is presented. A data element used to transfer data from FDS to FEM codes, the adiabatic surface temperature, is discussed. A tool named fire-thermomechanical interface is applied to transfer data from FDS to ANSYS. A high temperature stress-strain model for structural steel developed by NIST is included in the FEM analysis. Compared to experimental results, the FDS-FEM method predicted both the thermal and structural responses of a steel column in a localized fire test. The column buckling time was predicted with a maximum error of 7.8%. Based on these results, this methodology has potential to be used in performance-based analysis.